Apparatus for roasting and sintering ores.



J. B. GREENAWALT. APPARATUS FOR BOASTING AND SINTERING ORBS.

APPLICATION FILED SEPT. 26', 1913.

Patented Mar. 3, 1914.

2 SHEETS-SHEET 1.

W1 TMESSES J. E. GREENAWALT.

APPARATUS FOR ROASTING AND SINTERING ORES.

APPLICATION FILED SEPT. 2a, 1913 1,088,818. Patented Mar. 3, 1914.

2 SHEBTS-SHEBT 2.

IVITNESS ES JOHN E. GREENAWALT, OF DENVER, COLORADO.

APPARATUS FOR ROASTING AND SINTERING ORES.

Specification of Letters Patent.

Patented Mar. 3, 1914;

Original application flledMarch 24, 1913, Serial No. 756,519. Divided and this application filed September To all whom it may concern Be it known that I, JOHN. E. GREENAWALT, citizen of the United States, residing at Denver, in the county of Denver and State of Colorado, have invented certain new and useful Improvements in Apparatus for Roasting and Sintering Ores, of which the following is a full, clear, and exact description. reference being had to the accompanying drawings. forming a part hereof.

My invention has relation to improvements in apparatm for roasting, sintering,

and otherwise treating ores and other material; and it consists in the novel features of construction more fully set forth in the specifieaticn and pointed out in the claims.

In the drawings. Figure 1 is a side elevation of an ore-sintering pan surmounted by an ignition hood, showing the appl cation of my invention thereto, parts being broken away: Fig. 2 is a vertical cross-section on the line 2-2 of Fig. 1; Fig. 3 is a part elevation and part-vertical middle section of a burner employed in connection with, and forming a component part of, my apparatus; Fig. 1 is a horizontal sectlon on the line 4-l of Fig. 3; Fig. 5 is a hor1- zontal section on the line of Fig. 3, parts being broken away; Fig. 6 1s a detached plan view of the slotted disk through which the burner fluid is sprayed; Fig. 7 is an edge view of Fig. 6; and Fig. 8 is a plan of a disk having a series of slots of unequal widths.

The present is a division of the subjectmatter of my original application for patent for improvements in oil burners, filed March 21, 1913, Serial Number 756,519 which matured into Patent Numbered 1,084,939, dated.Jan11ary 20, 1914. the subject-matter hereof being directed to apparatus for roasting and'sintering ores (or treat ing other material) en masse, where it becomes important to simultaneously ignite the entire surface of the charge in order to insure an even and un form propagation tberethrough of the zone of combustion.

This simultaneous ignition of an extended 4 c-cted, relative to the outer boundaries of thecharge, especially in processes where the Serial No. 791,976.

charge is subjected to the action of a downdraft current of air to supply the necessary oxygen to the combustible components of the charge. Instances of such downdraft for purposes of roasting, oxidizing, sintering and otherwise treating ores are to be found in my U. S. Patents 839,064 and 839.065, dated December 18, 1906, and in my pending application for sinterin apparatus, filed June 24, 1912, Serial lumber 705,495. Where, as in the latter example, a charge is sintered en massc, provision must. be made to effect a simultaneous ignition of the entire surface of said charge; and to accomplish this effectively, burners must be employed which will not only project the igniting fuel across the charge in paths substantially parallel to its surface, but with sufficient intensity or under suflicient head, to prevent material deflection of the projected streams, by the transverse currents of air traversing the body of the charge from top downward, such traverse as well understood, being due to the action of the exhauster producing the downdraft (or its equivalent). If the projected streams of igniting fuel or inflammable .ma' terial were deflected by the downdraft (or transverse current) to any material extent, a considerable proportion thereof would be sucked or drawn (or forced where pressure apparatus were used in lieu of an exhauster) into the body of the charge before said inflammable material or igniting fuel could be ignited above the charge, the portion thus prematurely drafted (or otherwise divertet into the charge being lost and rendered unavailable for the purpose for which it was intended.'

It is therefore one of the objects of my )resent. invention to providean ore-roasting or sintering apparatus of thei general character alluded to, in which pro 'ision is made to introduce the igniting fuel above the charge from points within the outer boundaries of the charge. said fuel being projected preferably inihe shape of inflammable material (gaseous. liquid or solid)- from points above and within the boundaries of the surface of the charge, toward said boundaries (that is to say outwardly) in paths substantially parallel to the surgas may ing the charge from top downward (or at right angles to the paths of projection of the igniting fuel).

A further object of the invention is having passages so disposed as to cause the I streams to follow paths substantially parallel to the surface of the charge, but I have found in practice that a burner the details a of which I shall presently describe is eminently adapted for the purpose here in view. I do not however, wish to be understood that the burner here illustrated and described is the only one available for use in i connection with my invention, as it is quite f obvlous that any burner or device operating in a manner substantially equivalent thereto is contemplated by my invention. Inasmuch as the burner (or its equivalent) forms an element of the combination relied on to bring about the results contemplated by the invention, the details of one form of burner will be described in connection with the ore holder or furnace with which it is associated.

The invention in detail including a description of the burner, may be described as follows :Referring to the drawings, and for the present to Figs. 1 to 7 inclusive, 1 represents a pan or treatment receptacle which lIIPI'aCtICB may be of any convenient size, the dimensions of that here shown being about twelve feet in length, seven feet wide, and two feet deep, the same being provided with grates G or equivalent perforated support for the charge m, the thickness of the charge being about twelve inches, and the upper surface thereof disposed substantially flush with theedges of the pan. The grates are raised above the bottom of the pan so as to leave a vacuum chamber 4 between the grates and said bottom, the pan being provided with hollow trunnions 5 (about which it is rotatable) communicating respectively with said chamber 4 and through casings R and pipes P, P, with a suitable eXhauster E. Adapted to be deposited on the pan directly over the scribed being in all essential particulars the same as in my pending application aforeaid, and being herein necessarily referred to in order to show their relation to the burner forming one of the elements of the present invention.

in the present application of my invention I employ two burners B. B, mounted on the root of the hood and discharging into the chamber '13, there being one burner on each side of the transverse axis of the hood, and removed equal distances from said axis, each burner thus covering or igniting an area six by seven feet, of the total area of twelve by seven feet of the ore charge. Mounted above the hood and supported thereby in any mechanical manner is an oil tank T, from the bottom of which leads a discharge T 7 communicating with an oil line 8 disposed parallel to the length of the tank and extending in opposite directions from said T '7, each branch of said line being provided with a suitable control valve V beyond which is located a standard Schuttc-Koerting strainer 9. the branches of the oil line discharging into the burner, through the top thereof. Tapping the oil tank at the top and communicating with the air space above the oil in the tank is a compressed-air supply pipe 11 provided with an air-valve 12, said pipe connecting to a suitable flexible hose 13 which leads to any suitable source of compressed air supply (not shown). The compressed air or other gas in the tank T above the surface of the oil discharges through a reducing valve, pop valve, or equivalent pressure-regulator 15,

into'an air-line 16, the said line running in opposite directions from the valve 1.), each branch discharging tangentially into its respective burner, the air-branches being likewise provided with a standard make of strainer 9. The novelty of the foregoing features resides of course in the relation of the several parts to one another, and not in the specific construction of any one element.

Directing our attention to the construction of the burner per se, and to its specific disposition within the igniting chamber the said burner is composed of two sections a, b, the former being hollow or tubular and substantially cylindrical in form, the

sections being united to one another by means of bolts 17 passed through the see tion 7) and through the basal enlargement 1/ of the section a. Between the sections there I is interposed a sheet metal plate or disk 18 or equivalent spacing member, the said disk resting on the inner face of the section L and being provided with a series of radial slots 8 open at the outer ends, the inner closed ends thereof terminating within the chamber C of the burner as shown, the disk having a central circular imperforate section it from the periphery of which the slots radiate. The slots thus-form radial channels with the opposin faces of the sections a, b, for the escape of t e oil from the chamber of the burner into the atmosphere. The portion h of the disk serves as a support for the central spreader or cone 19 which is secured to the disk and to the section b of the burner by a screw-bolt 20 or equivalent mechanical manner. The cone serves not only to hold the disk 18 firmly against the bottom section b, but it likewise serves to distribute, and direct the oil into, the several channels aforesaid. I The base of the cone 19 comes inside the closed terminals of the slots or channels 8, whereby free communication is afforded through the channels between the atmosphere and the chamber C (termed for convenience as the mixingchamber). The disk 18 is provided with holes for the accommodation of the bolts 17. I

As seen from the drawings, the plane of separation between the burner sections a, b, is at right angles or transverse to, the axis of the mixing ciamber, so that the paths of discharge of the oil and gases from the burner are in the corresponding plane, any oil not fully atomized being caught in the gutter 21 formed around the periphery of the burner-section b. The upper end of the burner-section a is provided with a hollow screw-plug 22 to which are respectively secured the discharge end of the oil-line branch 8 (the connection being made by an elbow 23 passed over the end of said branch and over a pipe 2-3 inserted into the plug), and a standard spray-nozzle 24, the latter being preferably of the Schutte-Koerting variety well known in the art. The axis of the spray-nozzle is coincident with the axis of the burner as shown, whereby the spray ofoil is symmetrical about said axis. The air line 16 communicates with the mixing chamber at the top thereof, the air being introduced preferably at a tangent to the inner wall of the chamber whereby a whirling movement is imparted to the air within the chamber. The connection is made at the opening 25 in the boss 26 of the wall of the section a. The spray-nozzle 24 reouires at least fifteen pounds pressure to spray the oil into the free atmosphere at normal temperatures, and some heavier oils require even more. The oil however, is sprayed into the chamber C which itself is under a pressure approximating forty pounds, so that the pressure required to force the oil into the chamber, other things being equal, will be fifteen plus forty pounds or approximately fifty-five pounds. The slots 8 though shown in the figures aforesaid as being of uniform size, may have one or more of them as s" enlarged over the other as shown in the modification in Fig. 8, such enlargement allowing a greater volume of air to pass through, and hence projecting further the flame at such poin s.

In the specific application of the burner as here shown, its success depends on the accuracy and perfection with which the oil is subdivided and delivered to the radial slots or channels 8. In other words, it is important that each slot or channel shall receive exactly the same amount of oil. This accurate subdivision follows to a considerable degree from the use of the spreader or cone 19, which as heretofore stated directs the distribution of the oil into its proper channels. The said subdivision likewise depends for its full realization on the use of the spray nozzle within the mixing chamber C whereby the oil is fully atomized or subdivided be fore it is delivered to the channels 8 (of which there should always be a plurality) through which the oil is dehvered in radial sprays or jets by the blastof air or other gas entering said chamber under pressure from the oil tank. The degree of ressure availed of to project the oil through and out of the channels depends on the area it is desired to cover with the flame; the greater the area the greater the ressure necessary to project the oil or resu ting flame. The air being under pressure flows through the slots or channels in proportion to the cross-sectional area of the slot, the volumes of air passing through the slots being equal if the crosssectional areas of the slots are equal, the projected streams being substantiallv of equal length. It will be seen that the streams of sprayed and atomized oil projected from the channels 8 being disposed in substantially the same plane, will collectively form an inflammable sheet of atomized fuel which when ignited will form a sheet or blanket of flame, said blanket (if sufiicient driving pressure be behind it) being coextensive with the surface of the charge 'and serving to simultaneously ignite the entire surface of said charge. To render this possible, it is of course obvious that the intensity of projection of the streams must be such as not to suffer any material deflection from their substantial parallelism with the surface of the charge (to be ignited) by the transverse air currents traversing the charge from top downward, in response to the action of the exhauster; otherwise some of the inflammable material or oil-spray would be drawn prematurely into the body of the charge and there lost, not having a. chance to form into flame before suffering the deflection referred to.

The operation of the'burner employed in the connection here described may be stated as follows :--Air under sixty (60) pounds pressure or more is delivered to the oil tank T into the space above the oil whereby the oil is delivered at said pressure to the spraynozzle 24, the said nozzle subdividing and spraying the oil into the mixing chamber. This subdivision of the oil permits each channel or slot 8 to receive its proper proportion of oil so that the resulting flame is one of uniform intensity and spreads over an extended area (each burner in fact discharging a flame coextensive with one-half the surface of the charge in the pan 1 The air as it passes from the tank flows through the reducing valve 15 which reduces the pressure say about eighteen pounds, thus allowing the air blast which enters (tangentially) the chamber of the burner to flow into said chamber at about a pressure of forty-two pounds (more or less), the consequent intimate mixture of sprayed oil and air passing into the channels 8 (at a pressure which will depend on the relation between the combined areas of the channels 8, andthe area of the opening 25), the oil being again atomized and sprayed as it discharges from the channels. The sprays being delivered substantially at right angles to the axis of the burner, and said axis being perpendicular to the (horizontal) surface of the charge m, it follows that the series of radial sprays thus projected from each burner will collectively form a sheet of inflammable particles which when ignited will result in a sheet of flame or in a burning blanket which in turn effectively and almost instantaneously (and before the inflammable particles can be prematurely deflected into the charge by the exhauster) ignites simultaneously the entire surface'of the section of the charge which is beneath said blanket, each burner thus igniting one-half of the surface of the ore charge, and both burners igniting the entire surface of such charge. Inasmuch as both burners work simultaneously, it follows that both sections of the surface of the charge will be ignited at one and the same time, so that the zone of combustion of the combustible components of the charge will propagate itself evenly and uniformly through the charge from top downward in the general direction of the transverse air currents drafted through the charge by the action of the exhauster. The burner here shown operates on a minimum amount of liquid compared with the size and intensity of the sheet-flame produced, and mav be used in many arts not necessarily akin to roasting or sintering ores.

The pressure difl'erential or excess of eighteen pounds pressure here alluded to under which the oil is driven into the chamber of the burner member against the pressure of air or gas maintained within said chamber for expelling the liquid. may of course vary. This difl'erential will depend in a measure on the kind of spray-nozzle used, on the radius of projection of the streams desired through the slots (or equivalent vents), the cross-sectional areas of the slots, and 011 a variety of circumstances. The proper difl'erentialhowever, can always be determined by the operator according to the Work to be performed. The 'driving pressure of the liquid should of course be in excess of the gas pressure maintained in the mixing chamber so as to insure the projection of the liquid into the chamber. It may be added that in lieu of liquid fuel any fluent material gaseous or solid, may be substituted. Y

In the practice of my invent-ion as'described, the oil sprayed from the burners may-be ignited either as the hood is being deposited over the pan, or it may be ignited after the pan is deposited, by a torch inserted through a torch-hole (not shown) placed where convenient, according to the wish of the operator. It may be stated in passing that by providing a spray-disk (such as 18, Fig. 8) with slots 8, s, of various widths (or unequal dimensions) I can vary the distance of projection through the different slots, and hence vary (to suit my purpose) the areal configuration or shape 1 of the resulting sheet of inflammable material formed by the sum total of all the sprays discharged from the disk. For-ex.- ample, by providing the disk with radial slots of equal dimensicns there results substantially a circular sheet of sprayed material; by varying the dimensions of some of the slots I could secure a square or polygonal sheet, so that any areal configuration of sheet is possible.

As in my pending application aforesaid, the hood II when deposited on the pan 1 makes a chamber 6 therewith above the charge. said chamber being sealed (atthe sides and ends) by reason of the tight joint made between the machined surfaces of the edges of the hood and pan respectively when said hood is deposited on the pan. In the present invention however, the streams of igniting .fuel or inflammable material are directed outwardly toward the seal between the hood and pan, instead of inwardly from points along the walls of the hood. This new arrangement has the advantages, (1) that by locating the spray-device or burner in the chamber 6 at a point within the outer boundaries of the charge, the projected streams have a less distance to travel to cover the area of the charge, thus insuring more positive and satisfactory results; and (2) in the event that the contacting surfaces between the hood and pan are not clean to insure a tight joint or seal when the hood is deposited on the pan preparatory to the ignition of .the charge, any air which would tend to leak into the-roasting chamber 6 through the imperfect joint or seal would be arrested or checked by the streams of inflammable material projected outwardly or toward and against the seal from the burner or equivalent spray device thus located within the chamber. The arrest and checking of any currents leaking through an imperfect seal is desirable as they tend to disturb, and interfere with the integrity of the zone of combustion, as pointed out in my pending application aforesaid. Generically therefore, the present improvement contemplates the projection of streams of inflammable material from a point or points within the roasting chamber, outwardly toward the boundaries of the charge treated, in planes substantially parallel to the surface of the charge; and where the charge is supported in a treatment vessel eoyered by a hood, the invention contemplates specifically the projection of the streams from a point within the chamber toward the seal or joint between said vessel nd hood, it being understod of course, that the projection of the streams is under sutli cient head so as not to suffer material de flection by the transverse currents traversing the charge.

Features shown but not alluded to are old in the art, or are already embodied in my pending application aforesaid, and a description of the same is here unnecessary, especially as they form no part of the present invention.

Having described my invention, What I claim is 1. In combination with a treatment vessel containing a charge, and provided with a chamber above the charge, means positioned in the chamber above the charge at a point within the outer boundaries of the surface of the charge, and operating to project inflammable material over said surface toward the boundaries thereof aforesaid.

2. In combination with a treatment vessel containing a charge, and provided with a chamber above the charge, means positioned in the chamber above the charge at a point within the outer boundaries of the surface of the charge, and operating to project inflammable material toward said boundaries, and means for directing the inflammable material so projected, in paths substantially parallel to the surface of the charge.

3. In combination with a treatment vessel containing a charge, a hood'adapted to be deposited thereover andforming a chamber above the charge and means carried by the hood at a point above the charge and within the boundaries of the surface thereof, and operating to project into said chamber inflammable particles in paths substantially parallel to said surface.

4. In combination with a treatment vessel having a perforated support for the charge a hood adapted to engage said vessel and form therewith a sealed chamber above the charge when so engaged, an exhauster coupled to the vessel, and means in the chamber positioned above the charge within the outer boundaries of the charge, and operating to project inflammable material into the chamber in paths substantially parallel to the surface of said charge, and direct said material toward the seal aforesaid and toward the aforesaid boundaries of the charge.

5. In combination with a treatment vessel having a perforated support for the charge, a hood adapted to engage said vessel and form therewith a sealed chamber above the charge when so engaged, an exhauster coupled to the vessel, means in the chamber positioned above an intermediate point of the surface of the charge and operating to project radially outward, inflammable particles toward said seal in paths substantially parallel to the surface of the charge, and means for introducing a supporter of combustion through the hood into the sealed chamber.

(5. In combination with a treatment vessel having a perforated support for the charge, a member cooperating with said vessel and forming therewith a chamber above the charge, an exhauster coupled to the vessel, and means in the chamber positioned above the charge within the boundaries of the charge, and operating to project inflammable material into the chamber toward said boundaries, in paths substantially parallel to the surface of the charge. 1

In testimony whereof I aflix my signature in presence of two witnesses.

JOHN E. GREENAWALT.

\Vitnesses:

J. A. RAWLINS, H. LARSON. 

